1 8 Habit and Instinct. 



antecedent to individual experience. Young moorhens, as 

 soon as they are born and have recovered from the shock of 

 birth, can swim with definite accuracy of leg-movements. 

 Here the definiteness is not only congenital, but connate, if 

 we use this latter term for a congenital activity which is 

 definitely performed at or very shortly after birth. On 

 the other hand, young swallows cannot fly at birth ; they 

 are then too immature, and their wings are not yet 

 sufficiently developed. But when they are some three 

 weeks old, and the wings have attained functional size and 

 value, little swallows will fly with considerable if not 

 perfect skill and power. The definiteness is congenital, 

 for it is not acquired by individual experience ; but it is 

 not connate, since it is not exhibited at or shortly after 

 birth. The term deferred may be applied to such con- 

 genital activities as are performed when the organism has 

 undergone a certain amount of development after birth. 

 The definiteness of the swimming instinct in the moorhen 

 is congenital and connate ; the definiteness of the instinc- 

 tive flight of the swallow is congenital, but deferred. 

 Whether we apply the term " connate " or the term 

 "deferred" to the instincts of fully developed insects — 

 those in the imago stage — depends upon the view we take 

 with regard to the new birth of the insect after its 

 chrysalis sleep. 



Let us now turn to the activities the definiteness and 

 the peculiar nature of which may be termed acquired in 

 contradistinction to congenital. If we throw to young 

 chicks several caterpillars, some nice, others nasty, the 

 birds will, in the absence of previous experience, seize them 

 without discrimination. But they will soon eat only the 

 nice ones, and leave the others untouched. Two or three 

 lessons of this kind will suffice. After that, if mixed cater- 

 pillars be thrown to them, they will with definiteness and 



